Electric lamp



Patented Sept. 14,1937

UNITED sArss Application April 25,

1 Claim.

This invention relates to electric lamps and more particularly to lampsof that type which are employed on motor vehicles, as clearance lamps orother warning lamps.

Lamps of this type are usually fastened upon the walls of the vehicle,and heretofore a considerable portion of the wall had to be cut out toreceive the body portion of' the lamp.

One of the objects of the present invention is to provide a lamp whichmay be applied to the side of the wall of a vehicle body without thenecessity of cutting. out any portion thereof to receive the body orcase of the lamp.

In lamps of this type now on the market, considerable difficulty hasbeen experienced with the electrical connections between the conductorwire and the lamp, and one of the objects of this invention is tosimplify and. otherwise improve upon these connections.

In the present day lamps of this type the electric lamp bulb is set atan angle to the major axis of the lamp, with the result that shadows arecast by the pillars which support the filament, thereby interfering withthe efficiency of the lamp bulb itself. I

With these and other objects and advantages in view, this inventionconsists in the several novel features of construction, arrangement andcombination of parts, hereinafter fully set forth and claimed.

The invention is clearly illustrated in the drawing accompanying thisspecification, in which:-

Fig. l is a central, vertical section through an electric lamp embodyinga simple form of the present invention showing the same applied to afragment of the wall of a vehicle body;

Fig. 2 is a front elevation of the lamp;

Fig. 3 is a front elevation thereof with the lens and electric lamp bulbremoved therefrom; Fig. 4 is a fragmental, detail, horizontal section,taken on the line 4-- l of Fig. 3; and

Fig. 5 is an enlarged central, longitudinal section, taken through theelectrical connection of the lamp, showing certain parts detached fromeach other.

Referring to said drawing, which is merely illustrative of oneembodiment of the invention, the reference character 6 designates afragment of a wall of a motor vehicle body, such as a truck 50 body orother motor vehicle body, and said wall is shown as composed of outerand inner metal sheets I, 8, between which is a wooden sheathing 9 andthermotic insulating material I ll. Obviously the wall may be of any ofthe conventional forms used in motor vehicle bodies.

1936, Serial N0. 76,352

The lamp II is. formed of a hollow disc-like case l2, open at its frontend and closed at its rear by a fiat wall l3, which is arranged to beplaced. contiguous with vthe'outer face of the metal sheet 7 of thevehicle body wall.

Projecting forward from the back wall is the annular wall M of the casewhich is formed with an annularshoulder [5 to receive a resilient washerIt, against which is placed the lens ll, usually of the. concavo-convextype shown. The annularwall I4 is formed with a rim I8 beyond theshoulder it, in which rim is an annular groove !9 that is arranged toreceive a resilient split ring 28 which bears against the outer edgeportion of the lens and effectively holds it in place against thewasher- For convenience in removing the ring 20, one end thereof isformed with a bent up part 2i, under which a nail or other pointed toolmay be inserted for the pur- ..pose of prying the ring out of thegroove. This. arrangement provides a simple means'whereby the lens maybereadily removed from the case to' obtain access to the interior thereof.&

Projecting back from the rear wall [3 of the case, inco-axial'alignmenttherewith,is a hollow boss 22 which is cast integralwith the rear wall. Formed in the internal face of the boss 22 .areoppositely disposed grooves in the form of bayonet slots 23-which extendfrom'the front face of the wall l3 along the internal' face of the boss,22 and have reversely bent extremities 2 which are adapted to receiveand hold the usual locking pins 25 on the shell 26 of the conventionalelectric lamp bulb Z'Lsuch as is used in lamps of this type. 35

In the hollow of the boss 22 is contained an electric connection C towhich is connected an electric conductor cord, 0, that leads to asuitable source of electric supply, as for instance a storage battery.

The electric connection C comprises a contact member 35 and asleeve-like'body 28 (see Fig. 5) formed of non-conducting material andhaving an annular flange 29 upon one end, against which one end of acoiled compression spring 36 engages, the other end of the spring beingarranged to seat upon an annular shoulder 3| formed upon the internalface of the boss 22.

Contained in the hollow of the sleeve-like body 28 and seated againstone end thereof, is the socket portion 32 of the electric contact member35. In the end wall of the socket portion 32 is an opening 34 throughwhich the flexible wires, 0 of the electric conductor cord, 0, extendinto the interior of the socket portion.

Threadedly held in the socket portion is a screw threaded plug 33 whichis formed with a tapered end 36, that co-operates with the taperedinternal end face 31 of the socket portion to clamp the wires, 0 of theconductor cord between them. The outer end of the screw plug is slotted,whereby a screw driver may be I, used to screw the plug up against thewires. 2 In attaching the conductor cord to the electric contact member35, the screw plug 33 is partially unscrewed from the socket portion,the flexible wires, 0 of the conductor cord are bared for a shortdistance and inserted through the hole 34 into the hollow of the socketportion 32. H

The screw plug is then screwed up tightly against the wires, therebyspreading them around the tapered end of. the plug and tightly clampingthe wires between the tapered faces of the" plug and socket portion 32.

With this construction and arrangement there is nodanger of shearing offthe fine wires, as is likely to happen in the present day lamps of thistype, but-on the contrary the fine wires are tightly gripped andeffectively fastened to the contact member. After the wires have beenfastened in place, the contact member is pushed back into the hollow ofthe sleeve-like body 28 and the entire electric connection moved backinto the boss 22 until the spring seats against the shoul- -der thereof.

The electric lamp bulb 21 is put in place by inserting the shell 26-thereof into the hollow ofthe boss-'22, with the locking pins 25 passingalong the bayonet slots 23 to the ends thereof and then turning the lampbulbuntil the pins engage in the reversely bent extremities thereof. Thecenter contact piece of the lamp bulb engages with the screw plug 33 ofthe contact member' 35 and moves the entire electric connection,

1:40 0, back against the spring, the latter then serv ing to hold thecontact screw of the electric connection in close contact with thecenter contact piece of the electric lamp bulb and also serving to seatthe locking pins of. the lamp bulb in the 45 reversely bent extremitiesof the bayonet slots. The fiat back wall l3 of the lamp casing isprovided with screw holes 38, through which screws 39 may be insertedand driven into the wall of the vehicle. At the place in the wall of"'50 the vehicle where'it is desired to apply one of the lamps, a hole40 is bored into'the wall to receive the boss 22 and a vertical holeorother passage 4! is made in the wall to receive the conductor cord, 0.The boss 22 is inserted into the hole 40 and the screws 39 are driven inthrough the screw holes 38 into the wooden sheathing of the wall.

It is to be observed that the electric light bulb is located co-axiallywith the axis of the lamp case, and this brings the filament of the lampto a position in which neither of the pillars thereof cast any shadowstoward the lens.

In case it becomes necessary to renew the electric lamp bulb the lensmay be readily removed by first prying the spring ring out of thegroove, thereby obtaining access to the interior of the case.

In the event that any repairs need to be made on-the electricalconnection, the latter may be readily drawn out of the boss and repairedor replaced.

We. claim as new and desire to secure by Letters Patent:

In an electric lamp, a castmetal disc-like case comprised of a fiat backwall having an annular lens holding flange projecting forwardly from themargin of the front face of the back wall, and a centrally disposedhollow boss-projecting rearwardly from the rear face thereof, the bosshaving a narrow annular internal shoulder formed at its rear extremitydefining a large opening within the shouldered part, and the hollow inthe boss-between said shoulder and the front face of the back wall beingof greater diameter throughout than that of the openingat the extremityof the boss, there being oppositely disposed bayonet slots formed in theinternal face of the boss extending back from the front face of.the-back wall, adapted to receive the usual locking pins of an electriclamp, a flanged, centre-contact insulating block loosely held in thehollow of the boss and arranged for attachment to a conductor cord,which enters the boss through-the large opening at the rear extremityofthe boss, and a coiled compression spring interposedbetween theshoulder of. the boss and the flange of the block and arranged to pressthe centre-contact in the block against the centre-contact of theelectric lamp, the block, together with the conductor cord, beingcapable of withdrawal through the front end of the hollow boss.

CARL P. SORENSEN.

PETER GIMSE.

